The second irony is that the very title of the Environmental Protection Agency charges it with protecting the environment. One might think that the agency would understand its mission without needing to be reminded.

Let's drill down a bit into the case at hand, Massachusetts v. EPA.

Respected scientific opinion suggests to the Supreme Court that a rise in global temperatures and related changes in climate and environment have been caused by a large increase in the concentration of greenhouse gases in the atmosphere.

So it was that a group of private organizations subsequently petitioned the EPA to start regulating emissions of four gases, including carbon dioxide, under the Clean Air Act.

Believe it or not, the EPA takes the position that a causative relationship is not firmly established between greenhouse gases and increasing global surface air temperatures.

Section 202(a)(1) of the act requires the agency to prescribe standards applicable to the emissions of any air pollutant from any class of new motor vehicles which, in the judgment of the EPA, contributes to air pollution that is anticipated to endanger public health or welfare. The Clean Air Act defines an air pollutant as any air pollution agent, including any physical, chemical substance emitted into the ambient air.

The EPA denied the private organizations' petition. The reasoning? The agency claimed that the Clean Air Act does not authorize it to issue mandatory regulations to address global climate change. Also, even if it had the authority to set greenhouse gas emission standards, the EPA thinks it unwise to do so. Believe it or not, the EPA takes the position that a causative relationship is not firmly established between greenhouse gases and increasing global surface air temperatures.(EPA, hello? Repeat after me: "Protect the environment.")

Joined by Massachusetts and other state and local governments, the petitioners sought review by a federal appellate court in Washington, D.C. Two of the three judges on that appellate panel agreed that the EPA properly denied the underlying petition. Not surprisingly, the matter was brought to the attention of the Supreme Court, which exercised its discretion to consider the case.

In a majority opinion authored by Justice Stevens, the Supreme Court reversed and remanded the case for further proceedings.

Specifically, the high court found that the harms associated with climate change are serious and well understood. Indeed, the government's own objective assessment of the science, along with a large consensus within the expert community, indicate that global warming threatens a rise in sea levels, irreversible changes to ecosystems, a significant reduction in snowpack, and increases in the spread of disease, as well as the ferocity of weather events.

Because of the EPA's failure to dispute factually the causative connection between greenhouse gas emissions and global warming, its failure to regulate such emissions actually contributes to the injuries of petitioners such as Massachusetts, according to the Supreme Court.

While the Supreme Court recognizes that the EPA's regulation of motor vehicle emissions alone may not reverse global warming, the court concludes that this does not obviate an obligation by the agency to take steps to slow or reduce this trend.

Moreover, because greenhouse gases actually do fit well within the Clean Air Act's definition of an air pollutant, the EPA has a statutory duty to regulate the emission of such gases from new motor vehicles, so holds the Supreme Court.

While the Supreme Court some years ago was the straw that broke the camel's back in Gore's presidential bid, the majority of its members have since come to understand the inconvenient truth of global warming and the EPA's significant role in regulating greenhouse gases. Consequently, they are ordering the EPA, the very agency charged with protecting the environment, to fulfill its statutory obligations to do so under the Clean Air Act.

Hopefully, we all will be able to breathe fresh air in relief as the EPA satisfies its mission going forward.